Apparatus for processing sheet material

ABSTRACT

Apparatus for processing sheet material of continuous length including a rotatable collection roll for accumulating the material and a compensating roll operatively associated therewith for influencing the takeup of the sheet material by displacement of the axis of the compensating roll to vary the length of the path of travel of the sheet material to the collection roll, and wherein means are provided for fixing the axial position of the compensating roll to prevent its causing backwinding of sheet material from the collection roll when the collection roll is temporarily stopped.

United States Patent 1 1 3,593,939

{ 2] Inventor Milton Bolles 2,988,297 6/1961 Pawlowski 242 7553 p g, 3,299,787 1/1967 Kolb et a1, 242 753 x [21 Ap N01 856,734 FOREIGN PATENTS PM Sept 1969 723 037 12/1965 c d 242/75 3 [45} Patented July 197] ana a [73] Assignee Deering Milliken Research Corporation Primary Examiner--George F. Mautz Spartanburg. S.C. Assistant Examiner-Milton Gerstein v Attorneys-Norman C. Armitage and H. William Petry {54] APPARATUS FOR PROCESSING SHEET MATERIAL 4 Claims, 4 Drawing Figs.

[52] L8. CL: .I I 242/75-5, ABSTRACT: Apparatus for processing Sheet material of 242/ 242/753 tinuous length including a rotatable collection roll for accu- [5 1] Int. C 1 1 v t 1 1 v 1 B651] l g the material and a compensating roll operatively as" 56315938 sociated therewith for influencing the takeup of the sheet Field of Search 1, 242/353, material by displacement of th axis 0f the compensating r0" 's], 781,785 to vary the length of the path oftravel ofthe sheet material to [59 :1:22:3533,211::5111;231:3332?531212151512? 2 9 2 4 l STATES PATENTS ing backwinding of sheet material from the collection roll 2 ,59 l 196 Pawlowskim '242/75.53

when the collection roll is temporarily stopped.

INVENT(.)R. MILTON M.BOLL ES PATENTfinJuLzolsn SHEET 3 OF 3 INVENTUR.

MILTON M. BOLLES 45 A ZTORNEY APPARATUS FOR PROCESSING SHEET MATMUAL This invention relates to the processing of sheet material in continuous length from and, more particularly, to apparatus for processing sheet material of indefinite length having improved takeup or collection means for the sheet material.

' It is common practice in the processing of continuous sheet materials, such as paper, textile woven and nonwoven fabrics, warp yarns,and the like, to collect such sheet materials on rotating beams or rolls and to provide a compensating, or dancer, roll in the path of movement of the sheet material to the collection roll to control the tension and/or the rate of takeup of the sheet on the collection roll. One specific use of such a takeup or collection arrangement is in apparatus for producing nonwoven textile net fabrics in which one or more sheets of spaced warp threads are combined with and adhesively bonded to a weft sheet of spaced generally parallel threads to form a composite nonwoven net product. Such nonwoven net fabrics are widely used as reinforcement in laminated products, such as synthetic polymeric sheets, paper sheets, and the like, and as support backings for carpets and multipart materials such as ceramic or wooden floor tiles. The fabrics may also be used as packing materials and as screening material for windows, doors and the like.

Upon formation, these nonwoven fabric sheets are appropriately collected on a beam or roll which is rotatably driven by suitable motor means. The speed of rotation of the collection roll and the tension in the sheet being fed thereto is controlled by the compensating roll, which is positioned in the path of movement of the sheet to the collection roll and is biased by suitable pressure means, such as air, in a direction generally perpendicular to the path of movement of the sheet to adjustably vary the length of the path in response to temporary tension variations in the sheet. Suitable control means are generally provided between the drive motor of the collection roll and the compensating roll so that changes in position of the compensating roll corrrespondingly change the rate of takeup of the collection roll to provide a more uniformly wound package.

in the use of such takeup equipment, it has heretofore been a problem that, during periods when the collection roll must be temporarily stopped during the winding operation, such as to repair or inspect a portion of the sheet upstream of the roll, or to remove a full collection roll, the pressure biased compensating roll tends to exert a path-dispalcing force on the sheet to cause backward rotation of the collection roll and unwind a portion of the previously wound sheet from the roll, resulting in an excess accumulation of sheet material immediately before the collection roll. This excess must be manually rewound on the roll before resuming the winding operation to avoid entanglement and possible breakage of the sheet. This problem of back-winding is compounded with the position of the compensating roll also controls the rate of takeup of the collection roll. A large displacement of the compensating roll from the normal path of travel of the sheet produces an excess speed input to the motor of the collection roll which, upon resumption of the winding operation, causes undue stresses and breakage of the sheet when the excess length is so quickly taken up on the collection roll.

it is therefore an object of the present invention to provide a continuous sheet processing apparatus having improved sheet takeup means which overcomes the problems of the prior art.

it is another object of the invention to provide apparatus of the type described having simple and economical means for positively fixing the position of the pressure biased compensating roll when the collection roll is stopped, thereby avoiding unwinding of the sheet material from the collection roll due to the biasing movement of the compensating roll.

The above, as well as other objects of the present invention, will be best understood and more fully described by reference to the accompanying drawings in which:

FIG. I is a schematic side elevation view of an apparatus for forming nonwoven net sheet material employing the improvements of the present invention;

FIG. 2 is an enlarged sectional view taken generally along line 2-2 of FIG. ii and showing the collection roll portion of the apparatus;

FIG. 3 is a right side elevation view of the collection roll and compensating roll of H6. 2; and

W6. 4 is a flow diagram indicating the pressurized fluid control mechanism for operating the compensating roll of the apparatus.

Referring more specifically to the drawings, FIG. 11 is a schematic side elevation view of an apparatus for producing a nonwoven textile net fabric sheet and incorporating the novel takeup features of the present invention. As shown, a continuous yarn strand or thread 10 is withdrawn from a supply package 12 and passes through a rotatable winding device consisting of a counterbalanced thread guide arm or tube 14, the outer end of which is disposed to rotate in a circle about the flared ends of a pair of spaced yarn support members consisting of axially rotatable helical springs, one of which 16 is shown. A motor i8 is suitably connected to and rotatably drives the tubular guide arm 14 and helical springs 16 to produce a weft sheet composed of spaced, generally parallel thread sections. Detailed operation of such a winding apparatus to produce a weft sheet is disclosed in French Addition Pat. No. 79,765 to French Pat. No. 1,208,968 and my copending US. Pat. Application, Ser. No. 798,044, filed Feb. l0, 1969.

Rotation of the helical yarn support springs advances the weft sheet of parallel threads between a pair of nip rolls 20 where they are combined with a pair of sheets 22, 24 of warp threads which are fed from a suitable supply, such as a warp beam, not shown. The combined contiguous sheet of warp and weft threads thereafter passes through an adhesive bath 26 where a suitable adhesive material, such as polyvinyl alcohol, is applied, after which the sheet passes about heated drying cans 28 to set the adhesive and is subsequently continuously collected on a collection roll or beam .30.

Positioned in the path of travel of the composite sheet 31 between the drying cans 28 and the collection roll 30 is a compensating roll 32 which engages the sheet and is pressure biased in a vertically upward direction, as shown, by fluid pressurized piston means, generally indicated at 34. As tension in the sheet 31 passing to the collection roll decreases, fluid pressure in the piston means 34 displaces the roll 32 and sheet 31 upwardly to increase the length of the path of travel of the sheet to the coiiection roll and correspondingly increase the tension in the sheet. Suitable control means 40 such as an electrical feedback control loop mechanism of the potentiometric type made by Reliance Electric Company operatively connects the compensating roll and the drive motor 42 of the collection roll to vary the rate of takeup of the sheet by the collection roll in response to variation in the position of the compensating roll 32.

Details of the compensating and collection rolls are best shown in FIGS. 2 and 3. As seen, the collection roll 30 is suitably supported for rotation on a frame member 50. The 586 shaft 51 of the collection roll is suitably connected by an endless flexible element 52 to the drive motor 42 which may be of a direct current, variable speed type. The composite nonwoven net sheet is directed to the compensating and collection rolls by guide rolls 54, 56 which are mounted on the frame 50 in the path of travel of the sheet before and after the compensating roll 32. The ends of support shaft 58 of the compensating roll 32 are rotatably supported in bearing blocks'59, 60 secured to the ends of piston rods 61, 62 of piston assemblies 64, 66 comprising piston means 34. Blocks 59, 60 are also slidingly secured in guideways 68, 70 for movement upwardly and downwardly in a. vertical direction, and the piston assemblies 64, 66 which may be operated by a suitable fluid pressure, such as air, are normally pressurized to biasingly urge the sheet 31 in a vertically upward direction. The pressure exerted by the piston assemblies 64, 66 is selected to counteract the force of gravity acting on the weight of the compensating roll and to obtain a desired tension in the moving sheet. The control mechanism 40 connecting the compen' sating roll to the drive motor 42 of the collection roll is of the conventional potentiometric type and operates to vary the voltage input to the variable speed motor 42 in response to variations in the position of the compensating roll along the guideways 68, 70 so as to increase the rotational speed of the collection roll 30 when compensating roll 32 moves upwardly due to decreased tension in the moving sheet 32, and to decrease the rotational speed of the collection roll when the compensating roll moves downwardly due to increased tension in the sheet being collected.

lt can be appreciated that in apparatus of the prior art when the collection roll is temporarily stopped to inspect and/or repair the continuous sheet upstream of the collection roll, tension in the sheet passing to the collection roll decreases, resulting in corresponding displacement of the path of the sheet by movement of the compensating roll in an upward direction under influence of the pressure piston assemblies 64, 66. This movement of the sheet imparts a counterclockwise rotational moment to the collection roll 30 which causes the sheet 31 to unwind therefrom and an amount thereof to accu' mulate before the collection roll. In addition, the upwardly displaced position of the compensating roll produces through control means 40 an increased speed input to the collection roll motor 42 so that upon resumption of the winding operation, the sheet is excessively stressed and often broken by the high rate of takeup of the excess sheet length previously unwound.

To alleviate this problem without the necessity of providing expensive and complex braking equipment on the heavy collection roll, means have been provided to positively fix the position of the compensating roll 32 when the motor 42 of the collection roll and the winding operation is temporarily stopped. As best shown in H0. 4, pressurized air from a suitable source, not shown, is normally supplied to the lower portionsof piston chambers 80, 82 of the respective piston assemblies 64, 66 through conduits 83, 84. A pressure regulator 85 is provided in the supply conduit 83 to permit establishment of a predetermined pressure in the lower portionsof the piston chambers and impose a predetermined upward biasing force on the compensating roll 32 through piston rods 61, 62. The upper portions of the piston chambers are normally vented to the atmosphere through conduits 86, 87 and an air filter 88.

To prevent upward movement of the pistons'fril, era when the collection roll motor 42 is stopped, there is provided an auxiliary air supply conduit 89 which connects, through a solenoid valve 90 and conduits 86, 87, the main air supply conduit 83 to the upper portions of the piston chambers 80, 82. A pressure regulator 91 is employed in the auxiliary conduit 89 to permit establishment of a predetermined air pressure in the upper portions of the piston chambers. Solenoid valve 90 is a three-way valve such as the Type 303 manufactured by Allied Control Company, Inc., and, as shown, is normally positioned to connect the upper portions of the piston chambers to the atmosphere. The valve 90 is connected by conventional electrical connection means (shown as a dashed line 92) to be actuated with energization and deenergization of motor 42.

In operation, when the collection roll motor 42 is energized, the valve 90 is positioned as shown in FIG. 4 with the upper portions of the piston chambers 80, 82 communicating with the atmosphere. When the motor 42 is deenergized, valve 90 moves to connect the auxiliary air supply conduit 89 with the upper portions of the piston chambers 80, 82 through conduits 86, 87. Pressure regulators 85, 9] are calibrated so as to produce a static condition to thereby fix the position of the pistons in the chambers 80, 82 and prevent movement of the piston rods and the compensating roll. When the motor 42 is reenergized, the valve 9t. returns to the position schematically illustrated in PK). 4 connecting the upper chamber positions to the atmosphere.

It can be appreciated from the foregoing detailed description of the invention that the control mechanism of the present invention may be employed in various continuous sheet handling afiparatus to positively fix the position of the compensating ro when the winding of sheet co lection operation is stopped thereby preventing backwinding of the sheet from the collection roll and improving the overall operation of the sheet handling apparatus. Although the pressure means for biasing the compensating roll is shown and described as pneumatic, it should be obvious that other pressure means, such as hydraulic, may be substituted therefore to perform the objects of the present invention.

The foregoing drawings and specification have set forth a preferred embodiment of the invention and, although specific terms have been employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being limited only by the extent of the following claims.

That which I claim is:

1. Apparatus for processing continuous sheet material com prising a collection roll, means for feeding a continuous sheet of material in a predetermined path of travel to said collection roll, drive means for rotating said roll to collect the sheet thereon, a compensating roll positioned in the path of travel of the sheet to said collection roll, pressure means biasing said compensating roll in a first direction generally perpendicular to the path of travel of the sheet to vary the length of the path in response to variation in tension on the sheet, and means operatively connecting said pressure means and said drive means to fix the position of the axis of said compensating roll when said drive means is stopped to prevent backwinding of the sheet from the collection roll due to the biasing movement of the compensating roll.

2. Apparatus as defined in claim 1 including control means operatively connecting said compensating roll and said drive means to vary the rate of takeup of the sheet in response to variations in the position of the compensating roll.

3. Apparatus as defined in claim 1 wherein said pressure means includes piston means including a piston chamber and piston operatively connected to said compensating roll for adjustably positioning the same, and means for introducing a first fluid pressure into the piston chamber on one side of the movable piston to bias the roll in said first direction and for introducing a second fluid pressure into the piston chamber on the opposite side of said piston in response to stopping of said drive means to maintain the axial position of said compensating roll fixed.

4. Apparatus as defined in claim 3 wherein said means for introducing fluid pressure to said piston means comprises fluid conduit means communicating with the piston chamber on opposite sides of said piston, pressure regulating means in said fluid conduit means for controlling the amount of pressure on each of the opposite sides of said piston in said piston chamber, and valve means in said conduit means operative in response to operation of said drive means for venting to pressure the portion pressure the portion of the piston chamber on said opposite side of said piston and for introducing said second fluid pressure thereinto in response to stopping of said drive means. 

1. Apparatus for processing continuous sheet material comprising a collection roll, means for feeding a continuous sheet of material in a predetermined path of travel to said collection roll, drive means for rotating said roll to collect the sheet thereon, a compensating roll positioned in the path of travel of the sheet to said collection roll, pressure means biasing said compensating roll in a first direction generally perpendicular to the path of travel of the sheet to vary the length of the path in response to variation in tension on the sheet, and means operatively connecting said pressure means and said drive means to fix the position of the axis of said compensating roll when said drive means is stopped to prevent backwinding of the sheet from the collection roll due to the biasing movement of the compensating roll.
 2. Apparatus as defined in claim 1 including control means operatively connecting said compensating roll and said drive means to vary the rate of takeup of the sheet in response to variations in the position of the compensating roll.
 3. Apparatus as defined in claim 1 wherein said pressure means includes piston means including a piston chamber and piston operatively connected to said compensating roll for adjustably positioning the same, and means for introducing a first fluid pressure into the piston chamber on one side of the movable piston to bias the roll in said first direction and for introducing a second fluid pressure into the piston chamber on the opposite side of said piston in response to stopping of said drive means to maintain the axial position of said compensating roll fixed.
 4. Apparatus as defined in claim 3 wherein said means for introducing fluid pressure to said piston means comprises fluid conduit means communicating with the piston chamber on opposite sides of said piston, pressure regulating means in said fluid conduit means for controlling the amount of pressure on each of the opposite sides of said piston in said piston chamber, and valve means in said conduit means operative in response to operation of said drive means for venting to pressure the portion pressure the portion of the piston chamber on said opposite side of said piston and for introducing said second fluid pressure thereinto in response to stopping of said drive means. 